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Huge emissions of CO2 have caused serious environmental problems. Photocatalytic CO2 reduction is an important strategy to solve this problem by using sustainable solar energy. Elemental photocatalysts remain underexplored in this context relative to metals or metal oxides. Herein, we discover that amorphous red P is able to selectively reduce CO2 to CO. Furthermore, a crystalline fibrous phase of red P with two parallel polyphosphide chains (consisting of 21 P atoms) has been synthesized and was used for CO2 reduction for the first time. Compared with amorphous P, the fibrous P with a periodical P atom arrangement exhibits a 10.5 times enhancement in CO2 reduction and an apparent improvement in charge carrier dynamics, supported by femtosecond and nanosecond transient absorption spectra. The CO2 reduction process at the gas–solid interface on elemental P is investigated by density functional calculations and the nudged elastic band method for the first time. The results indicate that CO2 can be easily activated by the P atoms on the surface. The breaking of the C–O bond is the key step and a proton-involving process is preferred during CO2 reduction. This work innovatively investigates CO2 reduction on elemental photocatalysts and helps to broaden the applications of elemental red P.

Background To describe the characteristics of patients with syphilitic uveitis in northern China. Methods A case series of 21 patients (33 eyes) diagnosed with syphilitic uveitis from 2011 to 2016 at a tertiary center in northern China was retrospectively analyzed. Results Twenty-one patients (33 eyes) were diagnosed as syphilitic uveitis. Posterior segment involvement was found in 32 eyes (97.0%). Vitreous haze, neuroretinitis, and posterior placoid chorioretinitis were mainly found in patients with a relatively short duration of the disease, while diffuse chorioretinitis, pseudoretinitis pigmentosa, cystoid macular edema, and epiretinal membrane were found in patients with relatively long duration of ocular involvement. A low best-corrected visual acuity (P = 0.022) and a delay of syphilis treatment (P < 0.001) were associated with a significantly worse visual outcome. Conclusions Syphilitic uveitis should be included in the differential diagnosis of any form of posterior ocular inflammation. The pattern of ocular involvement may change with the disease progression.